Qiuni Fu

Dr.-Ing. Qiuni Fu

Strength Degradation and Mechano-Sorptive/Creep Behaviour of Adhesively-Bonded Timber-Concrete Composite Systems

Timber-concrete composite (TCC) basically refers to element-level hybridization in which timber and concrete are combined to act as a single structural unit, such as composite bridge decks, composite slabs and beams. An ideal TCC element achieves a compatibility in strains at the interface between the two materials. Particularly, innovative adhesively bonded timber-concrete composite (TCC) systems allow nearly no relative slip between wood and concrete so that adhesive bond provides a much more rigid shear connection, compared with conventional mechanical connectors (e.g., nails, dowel, metal meshes, rods etc.). Besides, adhesive bonding requires no cut or drilling which could weaken the material strength, cause stress concentration, and create sites for corrosion.

However, the interfacial bond performance between wood and concrete, especially in long term, is not well known. There are many environmental and/or mechanical factors affecting the degradation of adhesive bonds. Wood under load, when subjected to moisture content changes, exhibits much greater deformations than under constant humidity conditions, which is called the mechano-sorptive phenomenon. Adhesive bond lines are suspected to have a similar behavior in this circumstance, which has negative effects on serviceability and even safety of adhesively-bonded TCC systems.

Consequently, Dr. Fu attempts to comprehensively study the long-term performance of adhesively-bonded timber concrete composite systems, including Obj. (1) strength degradations and life predictions of bond lines under various types of environmental conditions such as an alkaline solution in concrete pores, deicing saltwater and seawater, ultraviolet, freezing-thawing and wetting-drying cycles; and Obj. (2) mechano-sorptive ehavior of bond lines under combined constant mechanical loading and moisture cycling.